An ink jet recording method is a printing method in which droplets of an ink composition are allowed to fly and deposited on a recording medium such as paper to perform printing. This ink jet recording method is characterized by that images having high resolution and high quality can be printed at high speed. The ink composition used in the ink jet recording method is generally one mainly comprising an aqueous solvent and containing a coloring component and a wetting agent such as glycerin for the purpose of preventing clogging.
On the other hand, when printing is performed on a recording medium such as paper or cloth of a type that is hard for the aqueous ink composition to penetrate thereinto, or a plate or a film made of a material such as metal or plastics into which the aqueous ink composition does not penetrate, for example, a resin such as a phenol, melamine, vinyl chloride, acrylic or polycarbonate resin, the ink composition or a reaction solution is required to contain a component which can allow the coloring material to be stably fixed to the recording medium.
To such a demand, an ultraviolet curing type ink jet ink comprising a coloring material, an ultraviolet curing agent (polymerizable compound), a (photo)polymerization initiator and the like has been disclosed (for example, see patent document 1). Further, in this ultraviolet curing ink jet ink, various polymerization accelerators are used depending on its purpose.
Patent Document 1: U.S. Pat. No. 5,623,001
For example, amine compounds have been used for the purpose of preventing polymerization inhibition caused by oxygen. However, the amine compounds are not completely fixed into ink cured films even after the completion of ultraviolet curing reaction, and a phenomenon is observed in which they volatilize from the ink cured films after the elapse of a long period to contribute odors, or ooze out (bleedout) of surfaces of the ink cured films. Further, many of the amine compounds have toxicity to fish and give an environmental load, so that the use thereof has been unfavorable also in terms of the environment.
Furthermore, none which satisfies all of curing efficiency, surface curability, internal curability and prevention of the occurrence of cracks has been found in conventional ink compositions.